Double-chain-stitch sewing-machine



2 SheetsSheet l.

INVENTUR,

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A.- RONTKE. DOUBLE CHAIN STITCH SEWING MACHINE.

No. 582,691. Patented May 18, 1897 W/ TNESSES @102 j (No Model.) 2 SheetsSheet 2. A RONTKE DOUBLE CHAIN STITCH SEWING MACHINE.

Patented May 18,1897.

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UNITED STATES PATENT FFICE ALBERT RONTKE, OF ELIZABETH, NEW JERSEY, ASSIGNOR TO THE SINGER MANUFACTURING COMPANY, OF NEIV JERSEY.

DOUBLE-CHAlN-STITCH SEWING-MACHINE.

SPECIFICATION forming part of Letters Patent No. 582,691, dated May 18, 1897.

Application filed November 16,1894- Serial No. 529,018. (No model.)

To all whom it may concern.-

Be it known that I, ALBERT RONTKE, a citizen of the United States, residing at Elizabeth, in the county of Union and State of New J ersey, have invented certain new and useful Improvements in Sewing-Machines, of which the followingisaspecification,reference being had therein to the accompanying drawings.

My invention relates to that class of sewingmachines which form the double chain-stitch by means of an eye-pointed needle and a cooperating thread-carrying looper; and my invention has for its object to provide a machine of the class referred to which will be simple in construction and in which the movements are strong and positive, so that the machine will be adapted for very high speeds, the leading feature of the invention consisting in the looper-operating mechanism.

In the accompanying drawings, Figure 1 is a sectional side view of a left-hand-cylinder machine embodying my invention. Figs. 2, 3, and 4 are detail views of the take-up and controlling device for the needle-thread. Fig. 5 is a front end view of the machine with the face-plate of the head and the cap at the front end of the work-supporting arm or cylinder removed. Fig. 6 is a vertical section through the standard of the frame of the machine. Figs. 7, 8, and 9 are details to show the loopercarrier and its operating devices. Fig. 10 is an enlarged sectional detail on line- 10 10, Fig. 6, to show part of the looper-thread-controlling device; and Fig. 11, a detail view of the plate forming part of said thread-controllin g device.

The framework of the machine herein shown comprises the standard A, the overhanging arm A, and the cylindrical work-supporting arm A.

B is the driving-shaft, j ournaled in the lower part of the framework and extending longitudinally of the arm A said shaft having a crank I), connected by a pitman b to an arm 0 at the rear end of a rock-shaft O, journaled in the arm A, said shaft having at its forward end an arm 0, connected to the needlebar D, to reciprocate the latter vertically. Secured to and forming practically an extension or continuation of the shaft B is a sup plemental shaft B, the extreme outer end of which is bent to form the inclined crank b said shaft B being provided just rearward of said crank with an eccentric 17 E is the looper-carrier, and e is the eyepointed thread-carrying looper suitably secured to said carrier, the shank of said looper in the construction herein shown fitting in a socket in said looper-carrier and being removably secured therein by a set-screw e. The said looper-carrier is provided with forwardly-extending wings or flanges 6 which embrace the inclined crank b and said carrier is also provided on its opposite sides with laterally-extending pivots or trunnionse forming journals having bearings in blocks or bearing-pieces a, secured by screws a to the forward end of the arm A The loopercarrier is constructed with an opening e rearward of the wings or flanges 6 the side walls of said opening constituting a yoke in which the eccentric 19 works. Thus when the machine is in operation the crank b working between the wings or flanges 6 will impart 'a rocking movement to the -looper-carrier E on its pivot or trunnions 6 while the eccentric 19 working in the opening or yoke 6 imparts lateral movements to the looper-carrier, the pivots or trunnions e of the latter sliding laterally in their bearings in the blocks a.

The crank b 21-11d eccentric Z) are so arranged and timed relatively to each other that the looper 6 will in its vibrating or rocking movements pass forward on one side of the needle to take a loop of needle-thread, will then be moved bodily laterally,so as to rock backward on the other side of the needle as the latter descends for the next stitch, and passes its thread into a loop of the looper-thread, as is necessary in making the double-chain-stitch seam. As these rocking and sliding movements of the looper-carrier are all communicated from the operating-shaft B and are strong and positive, it will be obvious that this looper mechanism is comparatively noiseless and is well adapted for a high-speed machine.

The crank b and the eccentric b are both forward of the outer or forward bearing of the rotating shaft, by which they are carried or on which they may be formed, and the looper-carrier is thus adapted to be placed close to the outer or forward end of the worksupporting arm A (which is advantageous for some kinds of work,) and these operating parts are furthermore thus brought directly into contact with the parts of the looper-carrier to be operated by them.

On the shaft B is an eccentric b, forming part of the feeding mechanism, but as this mechanism is not herein claimed it need not be further described.

I is a removable cap, which in the form of machine herein shown serves as a housing for the looper and feed mechanism.

To properly handle the needle thread, I have provided a take-up and controlling device which I will now'describe. The needlebarD carries two separated plates (1, provided with thread-eyes, and between said plates is secured a thin plate or fin d to serve as a thread lifter or take-up.

F is a small bracket attached to the frame or head of the machine and having at its lower end a horizontal inwardly-projecting finger f, which is straddled by the threadeye plates (Z, said finger f and the lower part of the bracket immediately above it being grooved at f for the reception of the outer edge of the take-up fin (1'', said groove terminating at its upper end at the inclined ledge Attached to the bracket F is a light cheek-spring f the free lower end of which presses against the inside face of the part f of said bracket. The operation of this takeup and thread-controlling device is as follows: When the needle has descended to its lowest point, the parts are in the positions shown in Fig. 2, and theneedle-thread, which runs from the eye of one of the plates (1 to the other, will be drawn over the finger f, which thus draws the loop of needle-thread off fro1n the point of the retreating looper and also prevents too much slack from being taken down by the needle, and the formation of a loop on the side of the needle opposite that from which the looper is to take the needle-loop is avoided, this action being assistcd by the thread-lifting fin d, which as the needle rises lifts the thread from the finger f and carries it upward until the top of said fin reaches the top of the groove f at the inclined ledge f when the thread slips off from said fin, but is subsequently lifted by the eyes in the plates (Z far enough to properly set the stitch. \Vhen the needle next descends, the check-spring f momentarily detains the thread, and thus holds the slack up out of the way of the point of the descending needle. The thread is drawn beneath said check-spring f 3 on the descent of the needle-bar by the eyes of the plates d and is prevented by the finger f from being drawn below the lower end of said spring.

The looper-thread is controlled by a take-up device consisting of an arm G, attached to the lower end of the pitman Z) at the crank b of the shaft B, a stationary plate H, attached to the lower part of the standard A, and cooperating thread-eyes 72, also on said standard. The arm G is forked or bifurcated at its outer end to embrace or pass on both sides of the plate II, and the latter has an arm or portion 1L having at its upper part a convex edge h, which extends slightly within the concave grooved edge portion 71,2 of the plate II, there being space enough between these convex and concave edges for the passage of the thread, but the latter will be bent enough so that there will be a slight friction or drag thereon when passing between these two edges, one of which is partly housed within the other. Below the parts of the plates 11 and h, one of which is thus partly housed within the other, is an open slot h and the thread will be free from drag or friction when therein. The operation of this looperthre:ul take-up is as follows: \Vhcn the looper is retreating or making its backward movement, the takeup arm G is, in the rotation of the crank b, projected outward, as denoted by dotted lines in Fig. 0, so as to engage the thread running between the thread eyes or guides h and lift the same, and thus take up the slack occasioned by the backward movement of the looper, said arm Gmovin g in ward out of engagement with the thread before the looper has quite completed its backward movement. Before the arm G has become disengaged from the thread the latter has been lifted so as to be between the convex and concave edges 7t and 7L2, so that there will be a slight frictional drag thereon when the looper commences its forward movement, this frictional drag, while not amounting to an appreciable tension sufficient to constitute a thread-stop, being check enough on the thread to prevent slack as the looper moves forward and this frictional drag being entirely removed when the thread is drawn downward into the open slot 763.

Owing to the fact that the looper-carrier E is supported on both sides by pivots a so that power can be directly applied to said looperearrier centrally thereof, it will be obvious that the said carrier is so firmly supported that there will be no perceptible jar or vibration of the same in its movements, no matter at how high a speed the machine may be run; and this feature of providing supporting pivots or journals on both sides of said carrier on which it can rock therefore contributes largely to the efficiency of my invention as a high-speed and comparatively noiseless machine.

In the operation of an eyed or threadcarrying looper cooperating with the needle in the formation of a double-ohain-stiteh seam it is necessary that the movements of the looper in the direction of its length should be comparatively long, while the transverse movements of the looper to carry it 011 opposite sides of the needle are relativelyshort. My

new machine is so organized that the longitudinal movements of the looper are effected by rocking the looper-carrier E on its pivots or trunnions 6 so that there is but little friction in effecting the relatively long longitudinal movements of the latter, while the relatively short transverse movements of the looper-carrier are effected simply by sliding said carrier bodily laterally on its pivots or trunnions, and thus the different necessary movements of the looper-carrier are effected in a strong and positive manner and with a minimum amount of friction.

Having thus described my invention, I claim and desire to secure by Letters Patent 1. In a double-chain-stitch sewing-machine, the combination with a needle and its operating mechanism, of an eyed or thread-carrying looper, a Vibratin g and transversely-moving looper-carrier consisting of a bell-crank lever, and mechanism for imparting to said looper-carrier rocking movements in the direction of the length of the looper, and sliding movements transverse of the length of the looper, to vibrate the said looper and to move it laterally bodily.

2. In a double-chain-stitch sewing-machine, the combination with a needle and its operating mechanism, of an eyed or thread-carrying looper, a looper-carrier mounted to slide laterally and provided with wings or flanges and with a yoke, and a rotating shaft having a crank working between said wings or flanges, to vibrate said carrier, and an eccentric working in said yoke and thus serving to slide said carrier laterally.

3. The combination, in a double chainstitch sewing-machine, of a needle and its operating mechanism, a rotating shaft provided with a crank and an eccentric, the loopercarrier E provided with the looper e, the flanges or wings e embracing said crank, the pivots or trunnions e and the yoke or opening 6 embracing said eccentric, and suitable fixed bearings for said pivots or trunnions.

4. In a double-chain-stitch sewing-machine, the combination with the needle and looper and their operating mechanism, of a take-up and controlling mechanism for the lower thread consisting of the take-up arm G placed within the lower part of the standard A, and bifurcated at its outer end, operating mechanism for said take-up arm, the plate H having a portion 7&4 one edge of which extends slightly within a groove in said plate, to exert a slight frictional drag on the thread, at times, and stationary thread-eyes on opposite sides of and cooperating with said take-up arm and said plate.

5. Ina double-chain-stitch sewing-machine, the combination with a needle and an eyed or thread-carrying looper and their operatingmechanism, of a take-up and thread-controlling device for the needle-thread consisting of the fixed bracket F having the horizontally-projecting finger f, the groove f and the inclined ledge f above said finger, the thread-lifting fin or plate 61 and the plates d arranged on opposite sides of said fin or plate d and provided with thread-eyes which are below the top of the said fin or plate, the latter and the said plates 01 being connected to the needle-bar to be movable vertically therewith, said thread-eye plates d being arranged to straddle or pass on opposite sides of said finger f, and the said thread-lifting fin or plate 01 being arranged to have its outer edge project into the said groove f, the said finger f being so located relative to the movements of the thread-eye plates 61 that the eyes of the latter pass a considerable distance below the said finger when the needle-bar is in its lowest position, said plates cooperating with said finger to take up the slack thread and tighten the stitch during the downward movement of the needle-bar, and the said fin or plate d serving to lift the thread on the upward movement of the needle-bar until the top of said fin or plate d comes opposite the said incline f on the said bracket F.

In testimony whereof I affix my signature in presence of two witnesses.

ALBERT RONTKE. lVitnesses:

HENRY CALVER, J. F. JA UITH. 

